Uni-wale?

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Patricks Dad
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Uni-wale?

Post by Patricks Dad »

I've been pondering how to put gunwales on the Freedom Solo to minimize weight. I've seen references to something like this. Any opinions?

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Last edited by Patricks Dad on Mon Mar 07, 2011 9:16 pm, edited 1 time in total.
Randy Pfeifer
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TC in Twin Lake

uniwhale

Post by TC in Twin Lake »

I was thinking tthe same thing for my ranger. My only concern would be the gaps that you would und up with at areas along the inside and outside where the wood meets the fiberglass due to thickness variations in the hull but I bet some epoxy would fill it up nicely. With the lines of you canoe I bet it will work really slick!
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Post by FCPO »

PD,

Have you taken a look at how Martin Step does his on the Green Valley Boat Works site? When I was doing mine, I emailed Martin asking for some advice, and he very kindly not only sent me back some suggestions, but also a "drawing" on exactly how to do it. I'm sure you know the site, but for those who might not, here's the link:

http://www.greenval.com/FAQgunwales.html

Regards

George
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Patricks Dad
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Post by Patricks Dad »

George, I'm familiar with Martin Step's technique. It looks very nice (but still utilizes an inwale and an outwale). But I was pondering using the technique of lowering the stems to make room for my gunwale to avoid having to mill the ends of the gunwales to be thinner...

Thanks George.


TC, the inevitable gaps caused by inconsistent hull thickness can be minimized somewhat by sanding but not eliminated. But that gap can be moved to one side (inside) by using small wedges on the inside to ensure a smooth clean contact between the gunwale and the hull while then epoxy sets (and then filling the gap on the inside with thickened epoxy).
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Patricks Dad
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Post by Patricks Dad »

One source (probably where I got the idea for the uni-wale) for info on lightweight building - Jay Morrison. He covers lots of topics and does an excellent job.

http://www.paddlinglight.com/articles/l ... -tripping/
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Rick
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Post by Rick »

I've been pondering how to put gunwales on the Freedom Solo to minimize weight.
Jay Morrison (lightjay) used the routed gunwale pictured on one of his ultralight canoes... I believe he used cedar which would have dented easily, but still soft enough to chisel off and replace without too much problem.

My idea was to use a light 3/4 inch inwale of white pine glued in (white spruce would have been better but I couldn't get any), and a thin 3/16 outwale of hard white ash rabetted out to an L shape and then screwed on. This saved some weight compared to more massive ash inwales and outwales while keeping the outer corner of the outwale hard enough to resist denting.

Maybe a.compromise could be to use Morrison's method and fiberglass the top and outer side of the cedar... although that would dent white with time and might look worse than "character marks" on the outwales with ongoing wear and tear.
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Patricks Dad
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Post by Patricks Dad »

Rick, I'm thinking of a different compromise (which will weigh more than yours). I'm thinking of using a single piece of cherry (rather than Jay's cedar) to cut the weight but still get the durability of the cherry.
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Moonman
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Post by Moonman »

Hi Randy,

Why not just use the cherry in the normal fashion, parred down to smaller dimensions? If you use epoxy, which you will be using even with the routed approach, you are still going to get a lot of extra strength all along the hull. Probably the best thing to do would be to make up a couple test pieces with both approaches - then test for deflection and calculate mass of total cherry and weight. For example, if you took the 'extra' cherry that would be on top of the shear with the routed approach and added that dimension to the inwale or outwale (or split between the two), or eliminated it altogether, what would the strength and weight differences be?

On my Winisk my gunwales are: inwale of 1/2" wide x 3/4 deep cherry, with walnut scuppers of 1/4" wide x 3/4" deep x 3" long, outwales, cherry, 1/2" wide x 3/4"deep. Very strong, has held up for years and I don't baby that boat. I'll be building the Freedom solo as well and I'm planning on using the same basic approach but maybe thinning the gunwales even a bit more as we're talking about a shorter boat, much less beam, with the added shouldered tumblehome adding more strength.

If you do go the routed approach, I do think the solid one piece of cherry would look great though. The cherry just looks so nice, especially as it ages (oil finish).

Moonman.
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Patricks Dad
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Post by Patricks Dad »

Moonman,

Good thoughts. I have considered just ripping that gunwale and applying the 2 pieces in a conventional fashion. What intrigues me about this alternate approach is that it should be really easy to make and install (I would anticipate not needing a long series of clamps but instead a few straps around the hull to hold it down while the epoxy sets -the Freedom Solo has such little recurve in the sheer line). It probably does have some drawbacks however in getting a tight fit between the gunwale and the hull on both sides....

I also like the idea of a clean single rail without visibility/exposure to the edge of the hull or the top of the stems.
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Post by Moonman »

Hi Randy,

If I used that method I would do it for precisely that reason - looks. I think a dry fit would be definitely in order. If you do go that way, let us know how it goes and post some pics. Will you taper the bow and stern ends? What dimensions are you thinking of?

Moonman,.
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Patricks Dad
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Post by Patricks Dad »

my gunwale stock is 7/8 wide by 3/4 tall. that will leave the inwales and outwales about 1/4" wide each (after the channel is cut out). I probably won't taper that width any thinner but will likely taper the thickness (the 3/4" dimension) at the ends so it has some flow as it reaches the stems (as usual).
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Post by Moonman »

Sounds nice and light. What are you doing with your seats? Cleats? That's what I am leaning towards when I build the Freedom Solo. Are you going to weigh the gunwales before installation?

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Bryan Hansel
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Post by Bryan Hansel »

I think doing a scaled down gunwale, like Moonman said, would probably save more weight than a uni-gunwale, but the uni-gunwale will look pretty cool.

I just had this idea. Do a scaled down inwale and outwale and cap it with a thin strip. That'll minimize fitting problems and still give a capped look. Sounds like more work.

When do we get to see pictures? I'm really excited to see this boat finished.

Or if you really want to save weight, aluminum gunwales painted black, like this one:

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Moonman
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Post by Moonman »

Hi Bryan,

I see you used aluminum for all your trim. Is that a Freedom 17? What was the final weight?

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Patricks Dad
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Post by Patricks Dad »

In my circumstance, a uni-gunwale will be lighter given the wide (1/4"+) cut in the material to straddle the hull. If I were to just rip it, I most likely wouldn't make the resultant pieces even thinner (by planing them beyond the wood lost by the saw kerf). Both approachs could weigh exactly the same of course based on how the pieces are cut or milled. Strength/weight ratio will probably be different for a given weight (I would think that the traditional approach for a given weight is probably stronger - the extra weight for the "cap" portion of the uni-wale is probably not adding as much strength as it would distributed into one of the gunwales). I'm willing to give up some strength in favor of the look and ease of install (my speculation) and will depend on some strength from that shoulder chine (it's been a pain in the butt, it better have some pay-back).

I will weigh the gunwales before they are installed so I know where they land.

My plan for the seat is to use cleats on the hull. I'm pondering a seat design with a built-in yoke for portaging. I'm planning on tiny decks (contrary to my prior builds).

Pictures? Bryan, there are several pictures of this boat posted on this site from a couple guys who have finished their builds. But, pictures of my build (so far) can be found here:

http://www.facebook.com/album.php?aid=2 ... d0ba2b0a14
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